Fuel cell tie rod isolator

Abstract

A fuel cell includes a fuel cell stack. A pressure plate is arranged on one side of the fuel cell stack. The pressure plate includes a hole, and a tie rod assembly has a tie rod received in the hole. A nut with a conical surface is secured to the tie rod. An isolator is arranged in the hole between the tie rod assembly and the pressure plate. The isolator has a conical portion, and the conical surface engages the conical portion to provide a conical interface. The tie rod assembly applies a clamp load on the fuel cell stack via the conical interface.

What is claimed is: 
     
       1. A fuel cell comprising:
 a fuel cell stack; 
 a pressure plate arranged on one side of the fuel cell stack, wherein the pressure plate includes a hole; 
 a tie rod assembly having a tie rod received in the hole, and a nut with a conical surface secured to the tie rod; and 
 an isolator arranged in the hole between the tie rod assembly and the pressure plate, the isolator including a conical portion, the conical surface engaging the conical portion to provide a conical interface, the tie rod assembly applying a clamp load on the fuel cell stack via the conical interface, wherein the isolator includes a cylindrical portion extending from a narrow end of the conical portion and through the hole, the tie rod disposed in the conical and cylindrical portions, wherein the conical and cylindrical portions respectively include a conical portion terminal end and a cylindrical portion terminal end, at least one of the conical portion terminal end and the cylindrical portion terminal end extends from the hole and beyond an exterior surface of the pressure plate to provide electrical isolation between the tie rod assembly and the pressure plate. 
 
     
     
       2. The fuel cell of  claim 1 , wherein the conical portion engages the pressure plate in the hole. 
     
     
       3. The fuel cell of  claim 1 , wherein the both of the conical portion terminal end and the cylindrical portion terminal end extend from the hole and beyond an exterior surface of the pressure plate. 
     
     
       4. The fuel cell of  claim 1 , wherein the nut is arranged beneath the conical portion terminal end. 
     
     
       5. The fuel cell of  claim 4 , wherein the tie rod includes a threaded end secured to the nut, the nut is arranged interiorly of the conical portion terminal end. 
     
     
       6. The fuel cell of  claim 1 , wherein the isolator is plastic and is configured to provide electrical isolation between the tie rod assembly and the pressure plate. 
     
     
       7. The fuel cell of  claim 1 , comprising another pressure plate arranged on another side of the fuel stack assembly, the other pressure plate applying the clamp load on the fuel cell stack via the tie rod assembly. 
     
     
       8. A fuel cell comprising:
 a fuel cell stack; 
 a pressure plate arranged on one side of the fuel cell stack, wherein the pressure plate includes a hole; 
 a tie rod assembly having a tie rod with a threaded end received in the hole, and a nut with a conical surface and secured to the threaded end, the tie rod assembly applying a clamp load on the fuel cell stack via the conical nut; and 
 an isolator arranged in the hole between the tie rod assembly and the pressure plate, the isolator including a conical portion, the conical surface engaging the conical portion to provide a conical interface. 
 
     
     
       9. The fuel cell of  claim 8 , wherein the isolator includes a cylindrical portion extending from a narrow end of the conical portion and through the hole, the tie rod disposed in the conical and cylindrical portions. 
     
     
       10. The fuel cell of  claim 9 , wherein the conical and cylindrical portions respectively include a conical portion terminal end and a cylindrical portion terminal end, at least one of the conical portion terminal end and the cylindrical portion terminal end extends from the hole and beyond an exterior surface of the pressure plate to provide electrical isolation between the tie rod assembly and the pressure plate. 
     
     
       11. The fuel cell of  claim 10 , wherein the both of the conical portion terminal end and the cylindrical portion terminal end extend from the hole and beyond an exterior surface of the pressure plate. 
     
     
       12. The fuel cell of  claim 10 , wherein the nut is arranged beneath the terminal end of the conical portion terminal end. 
     
     
       13. The fuel cell of  claim 12 , wherein the tie rod includes a threaded end secured to the nut, the nut is arranged interiorly of the conical portion terminal end. 
     
     
       14. The fuel cell of  claim 8 , wherein the isolator is plastic and is configured to provide electrical isolation between the tie rod assembly and the pressure plate. 
     
     
       15. The fuel cell of  claim 8 , wherein the conical portion engages the pressure plate in the hole. 
     
     
       16. The fuel cell of  claim 8 , comprising another pressure plate arranged on another side of the fuel stack assembly, the other pressure plate applying the clamp load on the fuel cell stack via the tie rod assembly.